Not Applicable.
1. Field of the Invention
The present invention relates to apparatuses and methods for separation of a desired fluid from a fluid mixture. More particularly, the present invention is generally directed to a fluid separation assembly having a membrane permeable to a desired fluid and a wire mesh membrane support that supports the permeable membrane and has a barrier that prevents intermetallic diffusion bonding.
2. Description of the Invention Background
Generally, when separating a gas from a mixture of gases by diffusion, the gas mixture is typically brought into contact with a nonporous membrane which is selectively permeable to the gas that is desired to be separated from the gas mixture. The desired gas diffuses through the permeable membrane and is separated from the other gas mixture. A pressure differential between opposite sides of the permeable membrane is usually created such that the diffusion process proceeds more effectively, wherein a higher partial pressure of the gas to be separated is maintained on the gas mixture side of the permeable membrane. It is also desireable for the gas mixture and the selectively permeable membrane to be maintained at elevated temperatures to facilitate the separation of the desired gas from the gas mixture. This type of process can be used to separate hydrogen from a gas mixture containing hydrogen. Thus, in this application, the permeable membrane is permeable to hydrogen and is commonly constructed from palladium or a palladium alloy. The exposure to high temperatures and mechanical stresses created by the pressure differential dictates that the permeable membrane be supported in such a way that does not obstruct passage of the desired gas through the membrane.
One type of conventional apparatus used for the separation of hydrogen from a gas mixture employs a woven refractory-type cloth for supporting the permeable membrane during the separation process. The disadvantage of this type of conventional membrane support is that the cloth support is susceptible to failure when it is exposed to high mechanical stresses associated with the differential pressure required to effect diffusion through the membrane material.
Another conventional permeable membrane support is a metal gauze structure placed adjacent to the permeable membrane. The disadvantage of this type of support is that intermetallic diffusion bonding occurs between the membrane support and the permeable membrane when they are exposed to high pressures and high temperatures. The high pressure tends to compress the permeable membrane and the metal gauze together and the high temperatures tend to deteriorate the chemical bonds of those materials. Such undesirable condition results in migration of the molecules of the permeable membrane to the metal gauze membrane and the migration of molecules of the metal gauze membrane to the permeable membrane until a bond is formed between those two structures. This intermetallic diffusion bonding results in a composite material that is no longer permeable by the hydrogen gas.
Thus, the need exists for a method and apparatus for separating a desired fluid from a fluid mixture that can reliably withstand high operating pressures and temperatures.
Another need exists for a permeable membrane and support arrangement for separating a desired fluid from a fluid mixture, wherein the permeable membrane is not susceptible to breakage or intermetallic diffusion bonding.
Yet another need exists for a method of supporting a membrane that is permeable to a fluid, wherein the fluid permeable membrane is exposed to high temperatures and high pressures.
The present invention provides a fluid separation assembly having a fluid permeable membrane and a wire mesh membrane support adjacent the fluid permeable membrane, wherein the wire mesh membrane support has an intermetallic diffusion bonding barrier.
The present invention further provides a method for separating a desired fluid from a fluid mixture comprising a membrane that is permeable by the desired fluid, providing a wire mesh membrane support with an intermetallic diffusion bonding barrier, wherein the wire mesh membrane support is adjacent to the fluid permeable membrane, contacting the fluid permeable membrane support with the fluid mixture and contacting the wire mesh membrane support with the desired fluid permeating the fluid permeable membrane.
The present invention further provides for a method of making a fluid separation assembly comprising providing a membrane permeable to a desired fluid, providing a first retainer, providing a wire mesh membrane support having an intermetallic diffusion bonding barrier and placing it adjacent the fluid permeable membrane, providing a permeate member adjacent the wire mesh membrane support, providing a gasket adjacent the fluid permeable membrane, providing a second retainer adjacent the wire mesh membrane support and joining the first retainer, the gasket and the second retainer at their peripheries.
The present invention provides for a method for supporting a fluid permeable membrane comprising providing a membrane that is permeable by a desired fluid, and providing a wire mesh membrane support with an intermetallic diffusion bonding barrier, wherein the wire mesh membrane support is adjacent and supports the fluid permeable membrane.
Other details, objects and advantages of the present invention will become more apparent with the following description of the present invention.